https://imgur.com/a/sZKEjK0 On the right side of my yard, I built a dead hedge about a foot away from my fence so I can just spray roundup in between and at least keep this devil plant from creeping over more.
https://imgur.com/a/iOq9T5y
But on the left side, I want to completely remove it so that I can build a patio nearby. I've gotten them to the point where they're small, look terrible, but they won't fully die off.
For 2 summers I have been doing the following every few weeks. 1- cutting the stem, 2- bagging the stem so nothing drops anywhere and throwing it in the garbage 3- spraying roundup directly into the open stem, as well as the ground around it 4- waiting for new sprouts and repeat.
I've put off projects, it looks like shit, and I have a large part of my yard fenced off for my dogs safety. At this point I can't take it anymore. I just almost impulsively started digging the fuck out of the area but I contained myself.
I'm willing to do dig a 5 foot hole and filling it in with new topsoil if it'll work. Wtf can/should I do!?
by threeplane
2 Comments
1) Don’t spray the ground, that doesn’t do shit to the knotweed. This class of herbicides work by being absorbed through the green parts of the plant and carried down the vascular system into the roots. Not the other way around.
2) If glyphosate isn’t doing it, try triclopyr; USFS recommends cutting the plant at the beginning of the summer, then spraying the new growth in late summer. Injection methods (not the same as hack-and-squirt) are also effective.
3) Digging is likely to leave root segments behind, which will just resprout in a few seasons.
4) 3-5 years of occultation can also be successful, but it doesn’t sound like that’s what you want
[https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/fseprd529922.pdf](https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/fseprd529922.pdf)
It took us maybe 6 years to fully eradicate the knot weed that we inherited. We dug up what we could and every year we would carefully drop crossbow herbicide on the leaves. We haven’t seen any sprouts for the past 3 years. Good luck and be patient.